Web and sheet detecting assembly



2, 1965 s. E. CAMPBELL ETAL 3,215,793

WEB AND SHEET DETECTING ASSEMBLY Filed 001;. 21, 1963 2 Sheets-Sheet 1 INVENTORS Sf/EKELL E 4MPBELL AND BY DOA/4L0 E. FATEEMAA/ 52 77744071,, (afl/LMILM 2, 1965 s. E. CAMPBELL ETAL 3,215,793

WEB AND SHEET DETECTING ASSEMBLY Filed Oct. 21, 1965 2 Sheets-Sheet 2 /Z INVENTORS 26 Sh EEE-LL E. CAMPBELL AA/o BY DOA/ALB E. FATE/ZMAA/ A 1- TOR/(E Y5 United States Patent 3,215,793 WEB AND SHEET DETECTING ASSEMBLY Sherell E. Campbell, Rolling Meadows, Palatine Township, and Donald E. Raterman, Niles, Ill., assignors to Addressograph-Multigraph Corporation, a corporation of Delaware Filed Oct. 21, 1963, Ser. No. 317,579 12 Claims. (Cl. 20061.41)

The present invention relates to an assembly for detecting the presence of web or sheet material on a drum or rotating member and, more particularly, to such an assembly including means for preventing false or inadvertent operation of the assembly in response to eccentric or irregular movement of the drum or rotating member.

In many different types of web or sheet feeding or handling apparatus, it is desirable to detect the presence of the web or sheet material at different points during its passage through the apparatus. As an example, the copending application of Sherell E. Campbell and Donald E. Raterman, Serial No. 291,444, filed June 28, 1963, discloses a copying or printing machine for making one or more copies of an original in which the copy sheets are exposed by moving a superimposed original and copy sheet past a light source in contact with a rotating transparent drum containing the light source. A plurality of copies of an original can be made by selectively retaining the original on the drum at the end of one exposing operation and then detecting its continued presence on the drum to control the automatic feeding of an additional copy sheet to the drum for exposure. This detecting operation is conveniently performed by using a switch assembly having an operator which bears against the drum and which is actuated by contact with the web or sheet original on the drum to operate the switch. However, if the drum is subjected to irregular or eccentric movement, the switch assembly can be inadvertantly operated in the absence of sheet or web material on the drum.

Accordingly, one object of the present invention is to provide a new and improved sheet or Web detecting assembly.

Another object is to provide a new and improved assembly for detecting the presence of sheet or web material on a rotating drum or member.

A further object is to provide an assembly for detecting the presence of an element on a rotating member that is protected against inadvertent operation resulting from irregularities or eccentricities in the rotation of the member.

Another object is to provide an assembly for detecting sheets on a rotating drum which includes one wheel or roller bearing only on the drum for adjusting the position of the assembly in accordance with changes in the position of the drum and another roller or wheel normally hearing on the drum that is actuated by engagement with the sheet to provide an indication of its presence.

In accordance with these and many other objects, an embodiment of the invention comprises a sheet or web detecting assembly for detecting the presence of web or sheet material on the outer periphery of a drum rotating about an axis. The detecting assembly comprises a support mounted for pivotal movement about an axis spaced from and extending generally parallel to the axis of the rotating drum. A switch means is mounted on the sup port and is adapted to be actuated by a mechanism including a first roller or wheel movably mounted on the support in a position disposed in the path of movement of sheet or web on the drum. A second wheel or roller adapted to engage the drum at a position spaced from the path of movement of the sheet is carried in a fixed position on the support. The support together with the means ice carried thereon is resiliently biased toward engagement with the outer periphery of the drum sothat when the first wheel or roller encounters the leading edge of the sheet or web material on the drum, this first wheel is deflected to actuate the switch means to provide an indication of the presence of the web material, the web moving the first roller relative to the second roller and the support to which it is connected during the actuation of the switch. To avoid false operation of the sheet detecting assembly resulting from eccentric rotation of the drum, the second wheel or roller secured in a fixed position on the support continuously adjusts the position of the support and,

' thus, of the switch means to positions corresponding to the actual position of the drum so that movement of the first roller wheel means in response to eccentric movement of the drum does not result in relative movement between the first wheel means and the switch means and actuation thereof.

Many other objects and advantages of the present invention will become apparent from considering the following detailed description in conjunction with the drawings in which:

FIG. 1 is a fragmentary elevational view of a sheet or web detecting assembly embodying the present invention;

FIG. 2 is a sectional view taken along line 22 in FIG. 1;

FIG. 3 is a sectional View taken along line 33 in FIG. 2; and

FIG. 4 is a fragmentary top plan view of the web or sheet detecting assembly:

Referring now more specifically to the drawings, therein is illustrated a web or sheet detecting assembly which is indicated generally as 10 and which embodies the present invention. The assembly 10 is adapted for use with web or sheet feeding or handling apparatus and, in one particular embodiment, is adapted for use in a copying machine of the type disclosed in the above-identified Campbell and Raterman application in which it detects the presence of a flexible carrier 12 containing an original 14 on a rotating drum 16. The assembly 10 is actuated by the carrier 12 and original 14 to provide a signal to a control circuit in the copying machine indicating that an additional copy sheet is to be fed for exposure by the original to produce an additional copy of the original 14. The construction of the detecting assembly 10 is such that even though irregularities or eccentricities occur in the rotary movement of the drum 16, the assembly 10 provides an output signal representing the presence of the original 14 only when this original passes the detecting assembly 10. This assembly can also be used in a variety of other applications in which web or sheet material is fed by a moving body and in which it is desirable to detect the presence of the sheet or web material at a particular point in its path of movement.

The construction of the copying machine with which the detecting assembly 10 is shown is described and illustrated in detail in the above-identified copending application. In general, this machine includes the transparent drum 16 which is rotated about a fixed axis to move a superimposed copy sheet 18 (FIG. 1) and original 14, either with 93 Without the carrier 12, past a light source mounted in a fixed position within the transparent drum 16. During this movement, the copy sheet 18 and the original 14 are held in superimposed relationship against the outer periphery of the drum 16 by a flexible belt conveyor including one or more flexible belts 20 (FIG. 1). After the copy sheet 18 has been exposed, it is held in engagement with the belts 20 by a vacuum or negative pressure chamber of which the belts 20 form one wall, and the carrier 12 and original 14 are held in engagement with the outer surface of the drum 16 by a magnetic holding assembly indicated generally as 22 which is disposed at a fixed position within the drum 16 and which acts on magnetic portions on either the carrier 12 or the original 14. Thus, the exposed copy sheet 18 is separated from the original 14 to permit the exposed copy sheet 18 to be conveyed to a developing station and to permit the origihal 14 to be moved to the feeding station at which time another copy sheet 18 is placed in a superimposed position to permit the production of a second copy. In the copying machine disclosed in the above-identified application, this feeding of the copy sheet is performed by an automatic copy feeding assembly controlled at least in part by the assembly which detects the continued presence of the original 14 on the outer surface of the rotating drum 16. A

The web detecting assembly 10 includes a main support or plate 24 to which a bracket 26 is rigidly secured. The main support 24 and an arm 26a of the bracket 26 are provided with aligned apertures in which is received a 'sleeve 28 for mounting the support 24 for pivotal movement about an axis extending generally parallel to the axis of rotation of the drum '16. The sleeve 28 can be secured in position on the main frame of the machine by any suitable means, such as a pair of shafts 30 to which posed on the sleeve 28 between the arm 26a of the bracket and the support 24. This spring includes one end portion 34a bearing against one edge of the bracket 26 and another end 3412 received within an opening formed in an annular washer 36 that is secured in a fixed position to the sleeve 28 by a set screw 38. The axial position of the assembly 10 can also be adjusted by loosening the set screw 38 and sliding the assembly along the sleeve 28. The resilient biasing force provided by the spring 34 forces the assembly 10 toward the drum 16.

To provide means for adjusting the main support 24 to positions corresponding to the position of the drum 16 or for pivoting this support about the sleeve 28 in response to any eccentricities or irregularities in the rotation of the drum 16, the assembly 10 includes a drum engaging wheel or roller 40 'rotatably mounted on the reduced diameter outer end of a stud 42 by a lock Washer or other similar securing means '44 (FIG. 2). The inner end of the stud 42 is secured to a lower edge of a roller or wheel supporting plate 46 by a threaded fastener 48. The wheel or roller supporting plate 46 is secured to the main support 24 by a pair of threaded fasteners 50 (FIG. 3) which threadedly engage the plate 24 and which pass through elongated slots 52 in the plate '46. The drum engaging 'roller or wheel 40 is so disposed relative to the path of movement of the carrier 12 and the original 14 on the 'drum 16 as to be spaced outwardly from the adjacent edge thereof. Thus, the roller 40 is continuously biased into engagement with the outer surface of only the drum 16 by the spring 34. As irregularities or eccentricities in the rotary movement of the drum 16 occur, the wheel supporting plate 46 and the main support 24 to which it is secured are pivoted in a clockwise direction (FIG. 1) against the action of the spring 34 or in a counterclockwise direction under the action of the spring 34 to maintain the main support 24 in a desired spaced position from the drum 16 regardless of irregularities in the rotary movement of this drum.

To provide means for producing an electrical indication 'of the presence of the original 14 on the drum 16, the

with a block 60 of dielectric material interposed between the plate 56 and the switch 54. If desired, the switch '54 can be further insulated by a generally U-shaped dielectric element 62 covering the sides and terminals on the upper wall of the switch means 54. The element 62 is secured in position with one leg clamped between the switch 54 and the dielectric block 60 and the other leg portion engaged by the heads of the fasteners 58. The switch support 56 is secured to the wheel or roller supporting plate 46 by a headed fastener 64 which is received in aligned threaded openings in the plate 46 and a bracket 66 secured thereto and extends through an elongated slot 68 in the plate 56 and an elongated slot 70 (FIGS. 1 and 2) in the main support 24.

The switch means 54 is selectively operated by a roller or wheel 72 in response to the carrier 12 or the original 14 passing the detecting assembly 10. The roller 72 is rotatably mounted in a position engaging the outer periphery of the drum 12 in alignment with the path of movement of the carrier 12 or original 14 by a U-shaped supporting element 74. The roller 72 is rotatably supported between thelegs of the element 74 (FIG. 2) by a shaft formed by a headed pin 76 to the opposite end of which a lock washer or other fastening means 78 (FIG. 3) is secured. The shaft formed by the pin 76 is substantially aligned with the shaft 42 on which the wheel or roller 40 is mounted.

The U-shaped supporting element 74 includes a bight portion disposed immediately below the operator element 54a for the switch 54 to which is secured one end of a flexible supporting arm 80. The other end of the arm 80 (FIG. 3) is secured to a lug 46a which projects outwardly from the wheel supporting plate 46. The supporting arm 80 as well as the rigidly mounted deflector member 82, which guides the lead edge of the carrier toward the drum and into the path of roller 72, are secured to the lug 46a by a headed fastener 84 and a nut 86. The free end of the deflector 82 is disposed immediately adjacent the outer periphery of the wheel or roller 72.

The assembly 10 includes means for adjusting the positions of the wheel support plate 46, the switch support plate 56, the rollers 40 and 72, and the switch means 54 relative to the sleeve 28 on which the assembly 10 is supported. This means includes an adjusting screw '87 which passes through an opening in a flange 46b (FIG. 1) in the wheel support plate 46 and a similar opening in a flange 24a on the main support 24 to threadedly engage a nut 88. A compression spring 89 interposed between the flanges 46b and 24a biases the flange 46b against the head of the adjusting screw 87 and the flange 24a against the nut 88. By loosening the two fasteners 50 (FIG. 3), adjustment of the screw 87 moves the flanges 46b and 24a toward and away from each other to adjust the relative positions of the main support 24 carried on the sleeve 28 and the wheel support plate 46 on which the rollers 40 and 72 and the switch means 54 are carried. This relative movement is permitted by the elongated slots 52. When the adjusted position is reached, tightening the fasteners 50 secures the plates 46 and 24 in their desired positions. This adjustment can be used, for instance, to control the time during a cycle of revolution of the drum 16 at which the signal produced by the actuation of the switch 54 is transmitted to the control circuit.

The detecting assembly 10 also includes means for independently adjusting the position of the switch means 54 relative to the wheel supporting plate 46 and, more specifically, relative to the roller or wheel 72 carried on the plate 46. This adjusting means includes an adjusting screw 90 which passes through aligned openings in a flange 56a (FIGS. 1 and 2) on the switch supporting plate 56 and a similar flange 66a on the bracket 66 secured to the plate 46. The inner or lower end of the adjusting screw 90 is threadedly secured to a nut 92,

and a compression spring 94 is interposed between the flanges 56a and 66a. By loosening the fastener 64, an adjustment of the screw 90 moves the flanges 56a and 66a toward and away from each other by compressing or permitting expansion of the compression spring 94. When the switch 54 is in its desired position relative to the roller or wheel 72 or the supporting structure or bracket 74 therefor, the fastener 64 is tightened to clamp the switch supporting plate 56 in its desired position. This adjustment is desirable, for instance, to control the amount of deflection of the roller or wheel 72 required to actuate the switch 54.

During operation of the copying machine, the drum 16 is rotated in a counterclockwise direction (FIG. 1) or a clockwise direction (FIG. 3) with the rollers or wheels 40 and 72 resiliently biased into engagement with the outer periphery thereof by the spring 34. When the leading edge of the carrier 12 or the original 14 approaches the detecting assembly 10, the position of the main support 24 is not affected because the roller 40 is disposed out of alignment with the path of movement of the original 14 or the carrier 12 and remains in engagement with the outer periphery of the rotating drum 16. However, as the leading edge of the carrier 12 passes beneath the roller 72, this roller moves upwardly by deflecting the flexible arm 80 in a counterclockwise direction (FIG. 3) about the end secured to the lug 46a so that the supporting bracket 74 moves upwardly to engage and actuate the operator element 54a for the switch 54. This controls the switch 54 to supply an electrical signal to the control circuit or other control means in the copying means indicating that the original 14 remains in position on the outer periphery of the rotating drum 16. The wheel 72 rolls across the upper surface of the carrier 12 or the original 14 during continuing rotation of the drum 16 and until such time as the trailing edge passes beyond this roller. At this time, the resilient arm 80 deflects the supporting bracket 74 downwardly toward the drum 16 so that the wheel 72 again bears against the outer surface of the drum 16. During this movement, the depression of the operator element 54a is terminated, and the switch means 54 is restored to its normal condition.

The construction of the web or sheet detecting means is such that eccentric or irregular movement of the drum 16 does not result in false or inadvertent operation of the switch means 54. If the switch means 54 were to be fastened directly to the supporting frame of the copying machine, any irregular movement of the drum 16 directly inwardly toward or outwardly from the axis of rotation of this drum would result in a corresponding movement of the roller or wheel 72 and a consequent actuation or release of the switch means 54. To prevent this, the arrangement embodied in the detecting assembly 10 is such that relative movement must occur between the wheels 40 and 72 in order for the switch means 54 to be operated, either actuated or released. More specifically, whenever any eccentric movement of the drum 16 occurs, the roller 40 which engages only the drum 16 makes a corresponding change in the position of the main support 24. Since the roller 72 and the switch means 54 are carried on the support 24, the spacing between the supporting structure 74 and the switch operator 54a remains constant and the actuated or released condition of the switch 54 is not changed.

Although the present invention has been described with reference to a single illustrative embodiment thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An assembly for detecting the presence of web material on a rotating drum comprising means for positioning web material on the drum so that a side edge thereof is disposedin a desired position on the drum, a movably mounted supporting structure disposed adjacent the drum, a first drum engaging wheel mounted on said structure for rotation about an axis that is fixed relative to the structure, the first wheel being positioned at one side of the side edge of the web material to engage the drum and to be laterally spaced from the web material, a second drum engaging wheel mounted for movement relative to the structure, the second wheel being positioned on the other side of the side edge of the web material to engage the web material when the web material is provided on the drum, and switch means actuated by said second wheel and carried in a fixed position on said structure so that irregular movement of said drum moves the first and second wheels :by moving said structure and the presence of a web under the second wheel moves the second wheel relative to the structure to operate the switch means.

2. An assembly for detecting the presence of sheet or web material on a rotating roller or drum comprising a pivotally mounted support, a first engaging means fixedly mounted on the support in a position spaced beyond the edge of a web on the drum, a second engaging means movably mounted on the support to normally engage the drum and adapted to engage a web on the drum, and switch means fixedly mounted on the support adjacent the second engaging means so that movement of the first engaging means toward or away from the drum causes a corresponding movement of the support and switch means to prevent operation of the switch means and movement of the second engaging means due to engagement with a web moving the second engaging means relative to the support to operate the switch means.

3. In an assembly for detecting the presence of a layer on a drum rotating about an axis, a support mounted for movement toward and away from the axis of the drum, switch means mounted on the support, first engaging means movably mounted on the support and adapted to move relative to the support and the switch means carried thereon when the first engaging means engages a web on the drum, and second engaging means carried on the support and spaced out of the path of movement of a web on the drum to engage only the drum so that eccentric movement of the drum causes movement of the support and switch means toward and away from the drum to prevent relative movement between the first engaging means and the switch means that would result in improper operation of the switch means.

4. In an assembly for detecting the presence of a web on a member rotating about an axis, a support pivotally mounted for movement about an axis generally parallel to the axis of the member, switch means secured to the support, a first roller means mounted for movement relative to the support and disposed in the path of a web on the drum, means actuated by movement of the first roller means relative to the support for operating the switch means, second roller means carried on the support at a position spaced out of the path of movement of the web, and resilient means biasing the support toward the member to bias the second roller means into engagement with the member so that the position of the support varies in accordance with that of the member to prevent movement of the first roller means relative to the support except when displaced by engagement with the web.

5. The assembly set forth in claim 4 including means for adjusting the position of the switch means on the support in a direction generally transverse to the axis of the member.

6. The assembly set forth in claim 4 including means for adjusting the position of the first and second roller means in a direction generally transverse to the pivotal axis of the support.

7. The assembly set forth in claim 6 in which said arm is formed of flexible material and in which means are provided for rigidly securing one end of the flexible arm to the support.

8. The assembly set forth in claim 6 including a member movably mounted on the support, means securing the switch means to the member, and means for adjusting the position of the member to move the switch means toward and away from the second roller means.

9. An assembly for detecting the presence of a web on a drum rotating about an axis comprising a movably mounted support, first roller means mounted for rotation about a fixed axis on said support and adapted to engage the drum along a path displaced from the web, a second roller means adapted to engage a web carried on the drum, an arm movably mounting the second roller means on the support in a position aligned with the first roller means considered in a direction parallel to the axis, and switch means secured to the support and actuated by movement of the second roller means relative to the first roller means.

10. An assembly for detecting the presence of a web on a drum rotating about an axis comprising first drum engaging means adapted to engage the drum and movably mounted to permit the position of the first drum engaging means to be changed by variations in the position of the drum, second drum engaging means disposed in the path of movement of a web on the drum and adapted to move with the first drum engaging means when the position of the drum is changed and to move relative to the first drum engaging means during engagement with a Web On the drum, and control means responsive to relative movement between the first and second drum engaging means for producing an indication of the presence of the web on the drum.

11. An assembly for detecting the presence of a web on a shiftable element comprising first means engaging the element and movable to positions corresponding to the position of the shiftable element, second means adapted to engage a web on the element, means mounting said second engaging means for movement with the first engaging means and for movement relative to the first engaging means when the second engaging means engages a web on the shiftable element, and control means responsive to relative movement between the first and second engaging means for producing an indication of the presence of a web on the element.

12. The assembly set forth in claim 11 in which the first and second engaging means include roller means biased against the shiftable element.

References Cited by the Examiner UNITED STATES PATENTS 2,179,517 11/39 Pelosi 20061 X 2,798,912 7/57 Lindeman et al 20061 X BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

UNITED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,215,793 November 2, 1965 Sherell E. Campbell et a1,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 74 and column 7, line 3, for the claim reference numeral "6", each occurrence, read 9 -c Signed and sealed this 12th day of July 1966.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer Commissioner of Patents EDWARD J. BRENNER 

11. AN ASSEMBLY FOR DETECTING THE PRESENCE OF A WEB ON A SHIFTABLE ELEMENT COMPRISING FIRST MEANS ENGAGING THE ELEMENT AND MOVABLE TO POSITIONS CORRESPONDING TO THE POSITION OF THE SHAFTABLE ELEMENT, SECOND MEANS ADAPTED TO ENGAGE A WEB ON THE ELEMENT, MEANS MOUNTING SAID SECOND ENGAGING MEANS FOR MOVEMENT WITH THE FIRST ENGAGING MEANS AND FOR MOVEMENT RELATIVE TO THE FIRST ENGAGING MEANS WHEN THE SECOND ENGAGING MEANS ENGGES A WEB ON THE SHIFTABLE ELEMENT, AND CONTROL MEANS RESONSIVE TO RELATIVE MOVEMENT BETWEEN THE FIRST AND SECOND ENGAGING MEANS FOR PRODUCING AN INDICATION OF THE PRESENCE OF A WEB ON THE ELEMENT. 